Proper rpm drop cycling the prop during run up.

by **James Adair** » Sun May 25, 2008 2:14 am

I own a 71 260C. Cant find any information on what an exceptable rpm drop when cycling the prop during a run up. I was taught to go 300 rpm 3 times fast, no more than 500 rpm. (2000rpm run up) My mechanic says its too much and 100 is the max. Has anyone found the recommended procedure printed anywhere specifing the rpm? We do it every time we fly and don't think much of it. Thanks for any info! -Jim

by **ics-12766** » Sun May 25, 2008 2:42 am

My Killough book for a '65 260 (IO-540-D4A5), says, in the "Engine Run Up" section:

PROPELLER...CYCLE AS NEEDED TO CIRCULATE OIL AND EXERCISE GOVERNOR... NORMAL DROP 300 TO 400 RPM...

CAUTION.... DO NOT EXCEED A 500 RPM DROP FOR MORE THAN A FEW SECONDS AT A TIME.

The Killough books are good. ICS sells them thru Webco. See the FLYER.

by **Bernie Mazurek** » Wed May 28, 2008 7:32 pm

by **Michael** » Tue Nov 03, 2009 5:36 am

by **Kristin Winter** » Wed Nov 04, 2009 2:52 am

by **Jay** » Thu Nov 05, 2009 1:32 am

by **Effie Andree Wiltens** » Thu Nov 05, 2009 12:26 pm

by **Bruce Thumann** » Thu Nov 05, 2009 9:55 pm

James, an old A&P IA, and once Piper dealer taught me 1600 RPM, full pitch while watching the oil press guage, remove the pitch as soon as you see movement on the guage. Usually gets me about a 200-250 drop all three times. That was the procedure on my 69 C model and continues to be the procedure on my 72 C model.

Bruce

Proper rpm drop cycling the prop during run up.

Proper rpm drop cycling the prop during run up.

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